The present invention relates to pneumatic control valves, i.e. valves that control the inflow of fluid into a pneumatic actuator element, such as a bellows or a pneumatic cylinder to cause it to expand or to permit it to return to its contracted condition. Actuator elements of this type are used for many industrial purposes as precision actuators to move tools or measuring instruments to precise locations. For example such a precision actuator is disclosed in my U.S. Pat. No. 3,913,457.